Design and Simulation of Closed Loop Speed Control of DC Drives by Using Dual Converter

Abstract

This paper presents the speed control scheme of DC motor and provides a firing angle
based speed control technique of the separately exited dc motor. The best control characteristics of
DC motor have used in industries for different range of loading condition. A dual converter comprised
of two single phase AC-DC thyristor converter is proposed. Speed of DC motor is controlled by
controlling the armature voltage. Armature voltage is controlled using controlling the firing angle of
thyristor. The circulating operation of dual converter, in which rectifier 1 will be rectifying
(0<α1<90°) and rectifier 2 will be inverting (90°<α2<180°). By using the closed loop system
controlled the speed of dc motor with different loading condition using inner current and speed
control loop. The linear & non-linear regions are clearly visible in control characteristics. Firing
control scheme improve armature voltage & also reduce ripple content & possibility of discontinuous
conduction in circuit. The controlled performance exhibited is superior & also firing angle smoothly
controlled with fast response.